This invention relates generally to injection molding and more particularly to an extension member for mounting to a heated multiple-tipped nozzle in a well in a mold.
A key concern in injection molding is temperature of the pressurized melt as it passes through the runner system to the mold cavity. Thus, among other steps taken, the nozzle is usually heated, typically by an electrical element wrapped therearound. A difficulty arises, however, in the case of multiple-tipped nozzles, and particularly in the case of edge-gated nozzles, in that it is often difficult to extend the heating element all the way to the forward or mold end of the nozzle because it would interfere with the nozzle gating. Accordingly there is a need for a multiple-tipped injection molding nozzle offering improved temperature control adjacent the forward end of the nozzle.
In one aspect the present invention provides an injection molding apparatus comprising a plurality of mold cavities formed between at least one pair of mold plates, each cavity having a gate for communicating with an interior of the cavity, at least one injection molding nozzle body having a back end, a front end, at least one melt channel through the body and a heating member for heating the body, the at least one body capable of receiving heated pressurized melt from a source and capable of feeding the heated pressurized melt from the back end through the at least one melt channel to the front end, and a nozzle end mounted to the front end of the at least one body, the nozzle end having a bore therethrough extending from the melt channel at the body front end and communicating with at least two of the plurality of mold cavities, the nozzle end being made substantially of a material having a higher thermal conductivity than the at least one body.
In a second aspect, the present invention provides an improvement in an injection molding apparatus having at least one heated nozzle extending forwardly into a well in a mold, the well having a wall with a plurality of gates spaced therein, each gate extending to a cavity in the mold, the at least one nozzle having a rear end, a front end and a melt channel, the melt channel extending from an inlet at the rear end of the nozzle to an outlet at the front end of the nozzle, the improvement comprising a nozzle end mounted to the front end of the at least one nozzle, the nozzle end having a bore therethrough adapted to extend from the melt channel outlet at the front end of the nozzle and to communicate with the plurality of gates, the nozzle end being made substantially of a material having a higher thermal conductivity than the nozzle.
In a third aspect, the present invention provides an injection molding apparatus comprising at least one mold cavity formed between at least one pair of mold plates, the at least one cavity having a gate for communicating with an interior of the cavity, at least one injection molding nozzle body having a back end, a front end, at least one melt channel through the body and a heating member for heating the body, the at least one body capable of receiving heated pressurized melt from a source and capable of feeding the heated pressurized melt from the back end through the at least one melt channel to the front end, and a nozzle end mounted to the front end of the at least one body, the nozzle end having a bore therethrough extending from the melt channel at the body front end and communicating with the at least one mold cavity, the bore having a portion extending substantially perpendicularly to the melt channel, the nozzle end being made substantially of a material having a higher thermal conductivity than the at least one body.